Chemical Turns Stem Cells Into Beating Heart Cells

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日期: 2004-02-20 今日/总浏览: 1/4671 b3 ^% b# R9 V+ P+ e9 C# U

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Scientistshavefoundawaytoturnmouseembryonicstemcellsintobeatingheartmusclecells-aresultthatcouldleadtotheuseofembryonicstemcellsincardiactherapy,andpossiblyevendrugsthatcanpromptthebodytoregenerateheartcellsonitsown.
/ ~# w  h" r2 ?& `6 YTheresearch,whichappearsintheFeb.18printeditionoftheJournaloftheAmericanChemicalSociety,apeer-reviewedjournaloftheworld’slargestscientificsociety,tacklesanumberoftheobstaclesthwartingpracticalapplicationsofembryonicstemcells,whilealsopointingtoaviablepatharoundtheethicalandpoliticalconcernsencompassingthedebate.) S$ V8 ^7 ]$ G6 h9 n
Becauseembryonicstemcellscanturnintoanytypeofcellinthebody,manyscientistsbelievetheyholdincrediblepromisefortreatingavarietyofdegenerativediseases.Quiteafewscientifichurdles,however,standinthewayoftangibletherapiesforsuchmaladiesasdiabetes,Alzheimer’s,Parkinson’sandheartdisease.
$ k, C, u' n" Y  oWehavediscoveredasyntheticchemical,namedcardiogenol,whichcanselectivelydifferentiateembryonicstemcellsintobeatingcardiacmusclecells,saysXuWu,agraduatestudentinthelabofPeterG.Schultz,Ph.D,professorofchemistryatTheScrippsResearchInstituteinLaJolla,Calif.Embryonicstemcellsrepresentapotentiallyunlimitedsourceofcardiomyocytes-cellsthatcanrepairdamagedhearttissueinthebody-butuntilnowscientistshavebeenunabletocontrolthedirectionofembryonicstemcellstousetheminthetreatmentofheartdisease.3 E: ~6 _) l; P: i3 Y3 o
SchultzandhiscoworkersatScripps,includingWuandassistantprofessorShengDing,Ph.D.,screenedavastlibraryofcompoundsinsearchofmoleculeswiththepotentialtocausestemcellstogrowintoheartmusclecells.Theyfoundfoursuchmolecules,whichtheynamedcardiogenolA-D." P4 @# h" W& |2 x
Theytestedthecardiogenolcompoundsbyusingembryonicstemcellsfrommice.Aftersevendaysgrowinginatissueculturedish,themajorityofthestemcellswereconvertedintobeatingcardiacmusclecells.5 K$ \& v8 ^  C/ ?+ _
Whilethetestsweredoneonlywithmousecells,thefundamentalbiologyshouldtransferwelltohigherorganisms.Byusingthesemoleculestounderstandtheunderlyingbiology,itshouldbepossibletoextendthisdiscoverytohumans,Wusays.  \2 n! |1 m  D" i8 Z
InadifferentpaperpublishedrecentlyintheJournaloftheAmericanChemicalSociety,Dingandhiscolleaguesreportedthediscoveryofanothersmallmolecule-calledreversine-thatappearstoconvertadultcellsnormallyprogrammedtocreateskeletalmusclesbackintoprecursorcellswithsimilarpropertiesasstemcells.3 a1 m9 j+ U- Y9 Q- _
Thistypeofresearchmayultimatelyfacilitatedevelopmentofdrugsthatcanstimulatetissuestoregeneratethemselves,withoutanyneedtoharvestexternalstemcells,Dingsays.Wethinkthisrepresentsanexcitingmedicalopportunity.
1 g! D6 ^3 ^0 i! d; |* }Muchmoreworkisrequiredtounderstandthebiologicalpropertiesandmechanismsofreversine,butthesepreliminaryresultsraisethetantalizingpossibilitythatitmaybepossibletosynthesizeacompoundthatcreatesviablestemcellsfromadulttissue,Dingsays.Suchcellswouldnotberejectedbytheimmunesystem,sincetheycomedirectlyfromthepatientwhoneedsthem.
# y8 n( ^, x  q! y' U1 j& @Amoleculelikereversinecouldbecombinedwithacardiogenol-typemoleculetoproduceadrugthatkindlesregenerationofhearttissue.Almosteverytissuehasitsownreserveofstemcells,soultimatelywehopewedon’thavetoisolatethosecellsfromthebody,Dingsays.Wecanstimulatetissuetoregeneratebyjuststimulatingcellswithinthebody.
+ l* V5 w% P$ ~6 |# w$ UThistypeofregenerationalreadyoccursinanumberofnaturalprocesses.Inlowerorganisms,forexample,urodeleamphibianscanregeneratelostlimbsandtails.Inhumansandothermammals,thelivercanregeneratenaturally,Dingsays.Andyoungchildrencanevenregeneratefingertips.
* j: C# Y0 l( H" zAlloftheseprocessesaredirectedbymolecularsignaling.Ifpeoplecandevelopsmallmoleculetherapeuticstopreciselymimicandcontrolthosesignalsforcorrectingdefectsorrepairingdamagedtissues,youcouldeventuallybuythoseinapharmacyasaprescriptiondrug,Dingsays.! m: n. \: C$ s
Notonlywouldthisalleviatesomeoftheethicalconcernssurroundingstemcells,butalsoaless-frequentlydiscusseddownsidetostemcelltreatments:theirinvasiveness.Small-moleculetherapiesinvolvingregenerativemedicineareprobablyyearsawayfromclinicaluse.Atpresent,Schultz,Wuandothercoworkersarefocusingonunderstandingcardiogenol’smechanismofaction,anddesigningfutureexperimentstotestthesemoleculesindiseasemodels.. j: \% }- F7 |. b) t

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来源: American Chemical Society  t: Q& c6 @) _
发布者: 刘斌